Considering that I just finished a quilt with a tissue lamé binding, I guess I am not a purist. <VBG>
I have used a lot of polyester thread, and probably will still use it as it works, because I have a lot. But it is good quality poly thread. Have mixed some poly-blend fabrics in with cotton (but I also mix pre-washed and not washed fabrics in the same project on occasion.)
Never again will I try to applique with poly-cotton fabric though. Talk about difficult and fraying.
Here in the desert I have always preferred to sew with natural fibers. But blends were most abundant for a while.

If it works, it works.

Have fun,
Pati, in Phx

It depends on what I'm making and what my frame of mind is at the time.

Me too. I just finished, well almost finished, a wall hanging using upholstery samples.

I take low budget quilting to it's lowest possible point. LOL. For lining, I often buy mattress covers that are cotton, polyester or a blend at thrift stores, remove the fabric that makes it fitted and then use it to fill a quilt. They are usually very low priced, especially if bought on half-priced day. They come in the right sizes for twin, full, queen and king beds, and are also good to line potholders, place mats, table runners, hotpads, etc. Used blankets, flannel sheets and other things can also be used in place of buying batting. Once you wash these items with a good long cycle and some bleach, they are safe and clean to use and shrinking is not a concern. Neither is wadding, bunching and other issues that occur with some battings. Since I have so far tied my quilts, this has been an important issue for me. These mattress covers come in all thicknesses and qualities and are almost always white. You can select a thicker or thinner one, depending on what you want the quilt to be used for.
The very thickest would perhaps be hard to hand or machine quilt, but are great for pot holders, hot pads and table toppers. They do take the large stitch quilting well.

Yea kind of a mix for me depending on what I already have at home.

I'm not a purist, but both my DH and I are pretty "green". I tend to use all cotton or natural fibers. It's not something I have to do, just something I like to do. DH is an economist who studies renewable resources and inter-generational resources. I guess he finally has rubbed off on me after 30 years! LOL...

When I first started quilting, I was warned "Don't use polyester thread because it can tear the cotton fabric!" I've since found out that most cotton clothing is sewn with polyester thread. I can't think of anything that gets more use than a shoulder seam - and NO tearing! So... I now use polyester thread or whatever I have on hand. I do prefer to buy cotton for piecing because I don't like to deal with stretch. I haven't worked up the courage to try stretchy fabric as a backing. I'd love to try Minkee.

Cotton thread is great if it doesn't break off or get fuzz on your needle area. Some of these new threads do just that. Coats and Clark Star Cotton thread is not supposed to fuzz so bad. Has anyone else had this problem?

I am not a purist at quilting or anything else. I use 100% cotton fabric, cotton thread and only poyester batting. Not a snob either.

True but I am hoping my quilts last longer than any clothing does. I've had clothes that wear out after a year or two of seasonal wearing (less sometimes-they sure make them junky anymore).